High-pressure cutoff valve for dust pot assembly



June 8', 1954 2,680,451

VE FOR DUST POT ASSEMBLY HIGH-PRESSURE CUTOFF VAL Filed March 30, 1955 2Sheets-Sheet l/ I INVENTOR, 00N f//a L @Trae/EVS D. C. HILLV June 8,1954 HIGH-PRESSURE CUTOFF 2 Sheets-Sheet 2 Fil/ed March 30, 1953atentecl June 8, 1.954

UNITED STATI-:stv PATENT OFFICE HIGH-PRESSURE CU DUST POTA TOFF VALVEFOR SSEDTBLY Don C. Hill, Los Angeles, Calif. Application March 30,1953, Serial No. 345,338

. where high pressure gas in some manner reached the low pressuredistributing system. A failure of some portion of the low pressuresystem resulted in escape of inflammable gas` An explosion too-k place,causing heavy property damage and some loss of life.

It has been proposed to incorporate into low pressure gas distributingsystems safety devices which function to shut 01T How through the systemwhenever the gas pressure exceeds a predetermined limit. However, theinstallation of such safety devices in metropolitan districts isdiflicult and very expensive to accomplish. The gas mains, valves, etc.,

below busy streets and it vate additional chambers large number oflocations stalling safety shutoff is impractical to excabelow thestreets at a for the purpose of invalves. Moreover the necessary size ofsuch safety devices makes it impossible to locate them within theexisting vaults or chambers which are customarily located at intervalsalong the gas mains. Such vaults commonly contain a large filter unit,known in the art as a dust pot.

the installation of a separate shutoi valve device. In accordance withmy invention, I place a shutoff valve mechanism within a portion of thecommonly are located .y

The size of such vaults containing dust pots is not large enough topermit dust pot assembly and provide novelmeans for actuating the valvefrom a location within the vault but outside the dust pot assembly. Iprefer to separate the anges normally employed at the dust pot outletconnection and to place an intermediate flange between them. Thisintermediate ange need not take up more than one inch of space. Iprovide a radially movable rod, which extends through such intermediateflange, and this rod normally acts to hold open a springloaded shutoffvalve mounted within the dust pot A pressure-sensitive actuating deviceis mounted wthin'the vault adjacent the dust pot and connected to movethe said rod whenever abnormal pressure conditions exist. The device maybe installed Without enlarging the vault and.

therefore, tremendous savings can be effected in equipping a lowpressure gas distribution system with safety shutoff valves in ametropolitan area.

Accordingly, it is the principal object of my invention to provide ashutoi valve device in a dust pot assembly, which device is tripped byan external trigger rod located at the dust pot outlet connection.

Another object is to provide such a device in which the rod extendsthrough a relatively thin insert ange interposed between existingflanges normally used to connect the dust pot assembly to the downstreampiping or main.

Another object is to provide such a device in y which the valve closesin the direction of the applied pressure upon radial movement of thetrigger rod.

Another obj ect is to effective to close the valve whenever the gaspredetermined maximum .or Ifalls blow a predetermined minimum.

Another related object is to provide such a device which does not causeobjectionable restric- Vtion in ow of gas therethrough.

Other related and more detailed objects and advantages will appearhereinafter.

In the drawings:

Figure l is a sectional side elevation, in diaof the operating parts ofthe shutoff valve device. Figure 3 is a sectional side elevation showinga modified form of shutoff valve device.

Referring to the drawings, the vault, generally designated Ill and shownby the dashed lines in pot assembly H. This assembly II includes anouter shell or housing I2 having an inlet pipe I3 and an outlet pipe I4welded thereto. A lter unit I5 is positioned within the shell and isprovided with a lip I6 which rests on an annular supporting shoulder IlWithin the shell I2. The inlet pipe I3 is connected to the shell at alocation below the shoulder I'I and the'outlet pipe I4 is connected tothe shell at a location above the shoulder I'i. In this manner gasentering the shell I2 from the inlet pipe I3 must pass through the lterunit I5 in order to reach the outlet pipe I4.

In accordance with my invention, I separate the flanges i8 and I8 for asufficient distance to interpose a relatively thin intermediate flange2D. As shown in Figure 2, this flange 20 is connected to one end of asleeve 2l which extends axially within the outlet pipe I3. The forwardend of this sleeve is shaped to form a valve seat 22. A valve head 23 isprovided with a resilient disc 24 adapted to close against the seat 22to form a seal. rhis disc 24 is held in place bv means of a nut 25. Thevalve head 23' is xed to a stem 26 which extends axially through a pairof slide bearings 21 and 28. Bearing 21 is carried on a ported spider 29and the bearing 28 is carried on the boss 3U mounted on the support 3|.A radial opening 32 is drilled through the support 3l, shell 2l and ange20', and a trigger rod 33 slides within this opening.

A collar 34 is fixed to the stem 26 by means of set screw 35. Acompression spring 36 is interposed between the ported spider 29 and thecollar 34 and thereby exerts a force tending to move the stem 26 in adirection to close` the valve. The end of the trigger rod 33 is engagedby the end of the stem 2G to maintain the valve in open position. Whenthe valve is open, as shown in Figure 2, low pressure gas may flow fromthe interior oi' the dust pot through the sleeve 2l and into the main 31downstream from the flange I9. The openings through the ported spider 29are suiiiciently large so that very little resistance is offered to theflow of gas into the main 31 from the dust pot assembly.

The trigger rod 33 extends exteriorly of the dust pot assembly and isconnected to the pressure-sensitive actuator generally designated 38.The function of this actuator 33 is to move the rod 33 downward wheneverabnormal pressure conditions exist in the gas distribution system andthereby permit the spring 316 to close the valve by bringing theresilient disc 24 into seaiing engagement with the valve seat 22. Asdescribed below, the actuator 38 trips the rod 33 whenever the pressurein the main upstream from the dust pot assembly exceeds a predeterminedlimit. The actuator 38 may also be constructed so that it serves to tripthe rod 33 when the main pressure falls below a predetermined minimum.The latter function is desirable in order to effect a shutoff in theevent a serious leak should occur in the piping downstream from the dustpot assembly.

As shown in Figure 2, the pressure-sensitive actuator 38 includes a base39, a spacer 4B and a cover 4l. A rst diaphragm 42 is positioned betweenthe base 39 and the spacer im and a second diaphragm 43 is positionedbetween vthe spacer de and the cover M. The trigger rod 33 is connectedto the upper diaphragm 43 by means of the tting 44 and diaphragm plates5.

The lower diaphragm d2 is provided with a weight t which is chosen tocorrespond to the desired operating pressure within the mains. The spaceil within the body 39 and below the diaphragm 42 is subjected topressure in the main downstream from the dust pot assembly via fitting48. The space B9 between the diaphragme and within the spacer di! isvented to atmosphere through port 55. The space 5I, within the cover itand above the diaphragm 43, is connected through fitting 52 to the maindownstream from the dust pot assembly.

A source of gas under relatively high pressure isl connected by means oftting 53 to the space 5-4 within the body 39. A valve disc 55 carried onthe stem 5e is adapted to close against the stationary valve seat 5l.Whenever the pressure within the space 41 falls below a predeterminedmagnitude, the weight 46 acting on the lower diaphragm 42 causes thelink 58 to swing the toggle 59 in a direction to move the link 60 andstem 56. The valve disc 55 is moved away from the seat 5l, therebypermitting relatively high pressure gas to pass from the space 54 intothe space El. This high pressure gas then passes through iitting 62 andaligned openings 53, B4 and 55, provided in the body 35, spacer 40 andcover 4l, respectively. This high pressure gas then enters the` space 5lthrough lateral port E5. The increased pressure above the diaphragmmoves the trigger rod 33 downward against the action of the spring 5i.Downward movement of the rod 33 moves its upper end out of the path ofmovement of the Valve stem 26, thereby permitting the spring 3S to closethe shutoff valve. In order to reset the valve in open position, it isnecessary to remove the upper ange G8 of the dust pot assembly. Accessmay thusl be gained to the fitting 69 attached to the valve head 23 andthe valve head and stem may then be moved back against the action of thespring 3G andV permit the rod 33 to move upward into latching position.

The detailed construction of the internal parts of thepressure-sensitive actuator 38 do not form any part of my presentinvention.

In the modiiied form of the device shown in Figure 3, a hinged offlapper valve i is employed instead or the `axially moving valvepreviously described. This dapper valve is connected by a pivot pin 'ilto a bracket l2 mounted exteriorly of the sleeve i3. A stern 14,slidably mounted in spaced bearings l5, is connected to the dapper valve'i5 by means of the link T5. A resilient disc 'ii xed on the valve 'i8is adapted to ciose against the valve seat 'I8 formed on one end of thesleeve 53. A coil spring i9 acts against the collar 35 fixed on the stem'it to move the stem in a direction to close the valve. The trigger rod33a extends through a radial opening 32a in the fiange 21a. The triggerrod 33a may be actuated in the same manner previously described. When itis moved downward, the spring 'i9 acts to close the dapper valve againstthe seat lt. The device may be reset in the manner described above.

Having fully described my invention, it is to be understood that I donot wish to be limited to the details herein set lorth but my inventionis of the full scope or" the appended claims.

I claim:

i. In a safety shutoi device for a low pressure gasv distributnigsystem, said system having a dust pot assembly provided with iiangedflow conducting pipe and located within a subsurface vault, thecombination of: a valve device having relatively movable cooperatingvalve elements, said device being positioned within said dust potassembly, resilient means within the dust pot assembly acting to eiiectrelative movement of the valve elements to ciose the valve device, adisc member positioned adjacent the flange or said pipe and having anopening, a trigger rod mounted to move in said opening and having aportion engaging one of said valve elements to prevent movement thereof,and a pressure-sensitive actuator within the vault operatively connectedto move said triggerV rod.

2. In a safety shutoi device for a low pressure gas distributing system,said system having a dust pot assembly provided with flanged outlet pipeand located within a subsurface vault, the combination of a valve devicehaving relatively rod.

4. For use in a gas distributing system, a dust pot assembly providedwith an outlet pipe havand a pressure-sensitive actuator outside thedust pot assembly operatively connected to move said trigger rod.

For use in a gas distributing system, a dust 5. pot assembly providedwith an No references cited.

